Machine tools that allow precise machining of a workpiece by moving the tool in a controlled manner are known. The position of the tool in time is defined here by the feed function, which is to be specified corresponding to the desired workpiece geometries. However, only relatively simple feed functions can be specified. In the case of grinding machines, for example, by turning potentiometers the operator is able to define values for different positions of the grinding wheel, such as contact position, where the grinding wheel meets the workpiece, changeover position, where the removal of material by semi-finishing commences, and final position, where the grinding wheel has reached the finished size, as well as values for the particular travel speed of the grinding wheel between two positions.
Furthermore, specification of the feed function is aggravated by the fact that errors may easily occur when entering values, and by the fact that the exact determination of the individual values requires the operator to have a certain level of experience in order to achieve the desired accuracies in the machined workpiece.